Tire tread



June 2 8, 1938'. ca. G. HAVENS 2,121,871

TIRE TREAD Filed July 25, 1935 GLEMV G. HAVENS INVENTOR.

Patented .lune 28, 1938 Q v v UNITED STATES PATIENT OFFICE Glenn G. Havens, Detroit, Mich., assignor to United States Rubber Products, Inc., New York, N. Y., a corporation of Delaware Application July 25, 1935; Serial No. 32,983

3 Claims. (01.152-209) My invention relates to tires, and in particua gravel road, are more'easily moved apart and lar to the treads of pneumatic'tires. More parpermit the stones to become lodged and retained ticularly, the invention relates to a tread conwithin the grooves between the ribs. In order struction whereby the tendency of the tread to to overcome this objectionable feature, I propick up stones is considerably reduced. vide circumferential projections 4 extending from 5 In the design of pneumatic tire treads the cur-.- the sides of the ribs, between the top of the tread rent tendency is toward decreasing the width and the base of the grooves. The projections {of the ribs or rows of antiskid elements, and are not adjacent to the bases of the grooves for increasing, the number of ribs and/or rows of the reason that it is desirable to maintain the tread elements. As a result of this construcbases of the grooves of a definite width in order 10 tionfthe ribs or rows of elements become more to prevent tread cracking at the groove bases. flexible laterally, thus increasingthe tendency I also find it advisable to maintain the upper of the tire to pick up stones or other objects and limit of each projection 4 a distance from the to retain-them. top of the tread substantially equal to the width Stone retention within the grooves .of the of the groove between the adjacent ribs 2. In 1.5 treads of pneumatic tires produces surface tenother words, as shown in Fig.2, the distance X .ysioh at the base of the grooves and induces should .be substantially equal to the width Y.

cracking at this locality. In addition, stones The projections 4 need not be continuous, but which are. picked up on a gravel'road and rewhere plain ribs are usedin the tread configurami y the tread cause an objectionable noise tion the projections 4 should be continuous or 20 W the tire-is run on smooth Pavement. substantially continuous in the-direction of the I It is, therefore, an object of my invention tO' groove walls. However, when thetread is broprovide a pneumatic tire tread which is Sub- 'ken' up to form rows of antiskid elements, the an y free from p k n up a d r tainin projections 4 may be of a length or lengths in stones d/or other hard obj ts. I conformity with the length of the various anti- 25 A further object of the-invention is to provide Skid elements, means for Preventing Stone D 9' Without As an example of the efficiency of tires em- I detracting fro the appearance Of'the 'bodying my invention, tests were conducted in These j s wil be more ap from the which the tires were run on gravel at a speed f llowin detailed description when co d of twenty-five miles per hour for two miles, and 30 5 vention;

in connection w th th a pa n aw the stones which were retained in the grooves in which: of the tread were then cou nted. .Next, the tires 1 s a perspective e in Section Of a were run a distance of one mile on concrete, and Portion of Pneumallic e embodying y the remaining stones again counted- The num Fig. 2 is an enlarged transverse view, in section, one mile on concrete, divided by the number o a port o of the tread s own in of stones at the end of two miles on gravel, -3 is asimilar view illustrat ng a d ij r gives the percentage of retention. On this basis, $1011 of the inllentionthe various treads were found to haveithe follow 40 In Fig. 1, ,I show a pneumatic tire I of coning ratings of efliciency, both in picking up 40 ventional construction having a plurality of ribs to es and i retaining them: 2 extending circumferentially around the crown 14 row ribbed tires pick up 1% retention 50% of the tire l and defining grooves 3. The ribs 2 10 ibb d u i k t ti 607 4 may-represent continuous members, or' they may row F a 'P be broken up to form rows of blocks or other 7 row n e 1resp 6 en 45 I armband elements a 7 Standard, conventional tires of It will be noted that the tread of the tire I is genelgl 2 composed of seven ribs, thus indicating that the S i g 1931 width of each rib is somewhat less than the here- I ep em er tofore conventionalribs. A type of-tread such as herein illustrated is' shown in particular in my Tires of present inventioncopending application, Serial Number 4,600, filed Pick-up V of the umberof stones p ked February 2, 1935.. up by a conventional tire, or 500% efiicienc Narrow ribs, because oi their lateral flexibilitx Retention or 500% efliciency in comparison upon engagement with stones, while running on with a conventional tire.

ber of stones retained in the treadat the end of 35 pick-up %-retention 100% 50 Thus it is demonstrated that a, tire embodying the features of my invention operates at a relatively high degree of eficiency to prevent stones from becoming lodged within the grooves between the ribs or rows of antiskid elements, by

reason of the position and functioning of the projections 4 relative to the width of the groove between the ribs 2.

In place of the double projections, shown in larly'at their bases.

While I have shown and described certain preferred embodiments of my invention, it will be understood that other modifications may be made therein within the spirit of the invention and the scope of the appended claims.

Having thus described'my invention, what I claim and desire to protect by Letters Patent is 1. A. pneumatic tire having a tread comprising a plurality of clrcumferentially extending traction elements defining grooves, and one or more projections extending laterally from the sides of the traction elements to form restrictions between the openings and the bases of said grooves, said projections being spaced from the bases of the grooves, and the outward principal surfaces of said projections being spaced from the road engaging surfaces of the traction elements a distance substantially equal to the width of said rooves.

2. A pneumatic tire having a tread comprising at least seven circumferentially extending ribs defining grooves, and one or more circumferential projections extending laterally from the sides of the ribs to form restrictions between the opening and the bases of said grooves, said projections being spaced from the bases of the grooves, and the outward principal surface of said projections being spaced from the road engaging surfaces of the ribs a distance substantially equal to tread comprising grooves some of which have overhangings ribs to provide a restricted width between their openings and the bases spaced from the groove openings a distance at least equal to the width of the grooves.

vGLENN G. HAVENS.. v 

